Piston rings of cast iron



United States Patent PISTON RINGS 0F CAST IRON Tage Debusmann Madsen, Goteborg, Sweden No Drawing. Application September 25, 1953, Serial No. 382,474

4 Claims. (Cl. 75-125) Piston rings for combustion engines, compressors, pumps and the like, are subject under working conditions in a cylinder to wear not only at the surface in contact with the cylinder but also at their surfaces engaging the piston grooves. These surfaces are at the same time exposed to considerable static and dynamic bending loads. When as often occurs, there is an unsatisfactory lubricating state between the peripheral face of the ring and the cylinder wall, it is mainly a matter of a friction wear ing. This disadvantage is increased by corrosion, e. g. in combustion engines by chemical attacking compounds generated by combustion, and also by moisture which is formed on the cylinder wall, by the presence of chemical attacking material in the scavenging air or that used for combustion, or by a content of similar attacking matter in the lubricating oil and so on.

Cast iron is generally used when making piston rings, and one is especially pretentious in ones demands concerning the structure, hardness and elastic qualities of this cast iron. The material of the piston rings are, as a rule, adapted to the cylinder material so that the best possible sliding or wearing qualities may be obtained.

As a rule the material of the piston rings is unalloyed. However, it is also known to alloy piston rings when stress is laid upon obtaining a preferred structure hardness and good strength qualities. Further, by using an alloy one aims at attaining an improvement of the strain of the ring under the influence of the working temperature. Finally, it is also known to.alloy the ring material in order to increase the corrosion resistance.

Experiments and working experiences on the subject have proved that it is suitable to alloy the rings with vanadium, titanium and copper in order to obtain good working conditions and the best possible co-operation with the cylinder materialespecially' with cylinders alloyed with vanadium, titanium and copper-at which the proportion between the contents of the different alloy elements should be chosen as follows:

the content of V should be at least 0.15% and maximum 0.45%. Suitably the content of V is about 0.3%.

Corresponding to the dimensions of the piston rings and to the mechanical stresses of the rings in the particular cases, to the expected wearing stresses, the working temperatures and the conditions in question for pos sible corroding attacks, the following alloy proportions have proved to be especially suitable:

1. V=0.15% Ti=0.06% to 0.08% Cu=0.60% to 0.80%

2. V=0.25% Ti=0.06% to 0.12% Cu=0.75% to 1.00%

3. V=0.35% Ti=0.12% to 0.16% Cu=1.00% to 1.25%

2,738,268 Patented Mar. 13, 1956 The remainder in all the above three cases essentially consists of cast iron.

Besides, phosphorus may suitably be added to the alloy in a proportion of about 0.15% to 0.60%.

Also small quantities of antimony (Sb) may advantageously enter into the alloy;

By this method, piston rings are obtained not only with a low wearing characteristic but also with increased strength values and provided with a considerably high vibration resistance and a capability of withstanding high ring strain in use.

The manufacture of piston rings from the mentioned composition are suitable especially as initial material for making of piston rings with a chrome finished surface owing to its high strength values and good strain resisting property.

I claim:

1. A piston ring for piston machines made of cast iron, especially for combustion engines, compressors, pumps and the like, preferably provided with cylinder liners of cast iron alloyed with vanadium, titanium and copper, which ring for obtaining a high resistance against friction wearing as well as corroding attacks are formed of cast iron which is alloyed with vanadium, titanium and copper in the following proportions:

the content of vanadium ranging from 0.15% to 0.45%.

2. A piston ring for piston machines made of cast iron, especially for combustion engines, compressors, pumps and the like, preferably provided with cylinder liners of cast iron alloyed with vanadium, titanium and copper, which ring for obtaining a high resistance against friction wearing as well as corroding attacks are formed of castiron which is alloyed with vanadium, titanium and copper in the following proportions:

7 wherein the alloy contains about 0.15% to 0.60% phosthe content of vanadium ranging from 0.15% to 0.45%, the ring having been given a greater hardness by heat treatment.

4. A piston ring according to claim 3, wherein the ring is provided with a chromed peripheral surface.

References Cited in the file of this patent Alloy Cast Irons Handbook, 2nd edition, pages 14, 15 and 252. Published in 1944 by the American Foundrymens Assn., Chicago, Illinois. 

1. A PISTON RING FOR PISTON MACHINES MADE OF CAST IRON, ESPECIALLY FOR COMBUSTION ENGIENS, COMPRESSORS, PUMPS AND THE LIKE, PREFERABLY PROVIDED WITH CYLINDER LINERS OF CAST IRON ALLOYED WITH VANADIUM, TITANIUM AND COPPER, WHICH RING FOR OBTAINING A HIGH RESISTANCE AGAINST FRICTION WEARING AS WELL AS CORRODING ATTACKS ARE FORMED OF CAST IRON WHICH IS ALLOYED WITH VANADIUM, TITANIUM AND COPPER IN THE FOLLOWING PROPORTIONS.: 